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arXiv · 2308.11325

$2\cdot 10^{-13}$ fractional laser frequency stability with a 7-cm unequal-arm Mach-Zehnder interferometer

Victor Huarcaya·Miguel Dovale Álvarez·Daniel Penkert·Stefano Gozzo·Pablo Martínez Cano·Kohei Yamamoto·Juan José Esteban Delgado·Moritz Mehmet·Karsten Danzmann·Gerhard Heinzel
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Abstract

To achieve sub-picometer sensitivities in the millihertz band, laser interferometric inertial sensors rely on some form of reduction of the laser frequency noise, typically by locking the laser to a stable frequency reference, such as the narrow-linewidth resonance of an ultra-stable optical cavity or an atomic or molecular transition. In this paper we report on a compact laser frequency stabilization technique based on an unequal-arm Mach-Zehnder interferometer that is sub-nanometer stable at $10\,\mu$Hz, sub-picometer at $0.5\,$mHz, and reaches a noise floor of $7\,\mathrm{fm}/\!\sqrt{\mathrm{Hz}}$ at 1 Hz. The interferometer is used in conjunction with a DC servo to stabilize the frequency of a laser down to a fractional instability below $4 \times 10^{-13}$ at averaging times from 0.1 to 100 seconds. The technique offers a wide operating range, does not rely on complex lock acquisition procedures, and can be readily integrated as part of the optical bench in future gravity missions.

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Victor Huarcaya, Miguel Dovale Álvarez, Daniel Penkert, Stefano Gozzo, Pablo Martínez Cano, Kohei Yamamoto, Juan José Esteban Delgado, Moritz Mehmet, Karsten Danzmann, Gerhard Heinzel. 2023-08-22. $2\cdot 10^{-13}$ fractional laser frequency stability with a 7-cm unequal-arm Mach-Zehnder interferometer. https://doi.org/10.1103/physrevapplied.20.024078

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